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Incorporation of Counter Ions in Organic Molecules: New Strategy in Developing Dopant‐Free Hole Transport Materials for Efficient Mixed‐Ion Perovskite Solar Cells |
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| Authors: | Jinbao Zhang Bo Xu Li Yang Alba Mingorance Changqing Ruan Yong Hua Linqin Wang Nick Vlachopoulos Mónica Lira‐Cantú Gerrit Boschloo Anders Hagfeldt Licheng Sun Erik M J Johansson |
| Institution: | 1. Physical Chemistry, Center of Molecular Devices, Department of Chemistry–?ngstr?m Laboratory, Uppsala University, Uppsala, Sweden;2. Organic Chemistry, Center of Molecular Devices, Department of Chemistry, School of Chemical Science and Engineering, KTH Royal Institute of Technology, Stockholm, Sweden;3. Nanotechnology and Functional Materials, Department of Engineering Science, Uppsala University, Uppsala, Sweden;4. Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and The Barcelona Institute of Science and Technology, Bellaterra, Barcelona, Spain;5. Applied Physical Chemistry, Center of Molecular Devices, Department of Chemistry, KTH‐Royal Institute of Technology, Stockholm, Sweden;6. Laboratory of Photomolecular Science, Institute of Chemical Sciences and Engineering, école Polytechnique Fédérale de Lausanne, EPFL‐FSB‐ISIC‐LSPM, Lausanne, Switzerland;7. State Key Laboratory of Fine Chemicals, DUT‐KTH Joint Education and Research Center on Molecular Devices, Dalian University of Technology (DUT), Dalian, China |
| Abstract: | Hole transport matertial (HTM) as charge selective layer in perovskite solar cells (PSCs) plays an important role in achieving high power conversion efficiency (PCE). It is known that the dopants and additives are necessary in the HTM in order to improve the hole conductivity of the HTM as well as to obtain high efficiency in PSCs, but the additives can potentially induce device instability and poor device reproducibility. In this work a new strategy to design dopant‐free HTMs has been presented by modifying the HTM to include charged moieties which are accompanied with counter ions. The device based on this ionic HTM X44 dos not need any additional doping and the device shows an impressive PCE of 16.2%. Detailed characterization suggests that the incorporated counter ions in X44 can significantly affect the hole conductivity and the homogeneity of the formed HTM thin film. The superior photovoltaic performance for X44 is attributed to both efficient hole transport and effective interfacial hole transfer in the solar cell device. This work provides important insights as regards the future design of new and efficient dopant free HTMs for photovotaics or other optoelectronic applications. |
| Keywords: | counter ions dopant free high efficiencies ionic hole transport material mixed ion perovskite |